Question

The wheels of a car are of diameter 80 cm each.How many complete revolution does each wheels make in 10 minutes when the car is travelling at a speed of 66 km/hour

Answer 1

time = 10 mins = 1/6 hrs

speed = 66 km/hr

now, distance = speed * time

         => distance = 66 * 1/6

         => distance = 11 km or 1100000 cm

diameter = 80 cm , radius = d/2 = 40 cm

      circumference or perimeter of wheel = 2 * 22/7 *40

      no of revolution = distance / perimeter or cicumference

                                  => 1100000 /  2 * 22/7 * 40

                                  => 1100000 * 7 /2 * 22 * 40

                                  => 4375 revolutions